Cook et al., U.S. Pat. No. 4,818,643, discloses an extrusion process of polymer electrolyte materials and/or cathode materials, optionally extruded onto other components of a cell, including current collectors, sequentially or by coextrusion. Example 8 therein describes the addition of propylene carbonate to a melt blend of polyethylene oxide and salt in a second extrusion stage.
Gozdz et al., U.S. Pat. No. 5,418,091, discloses a "dry film" process involving the use of a temporary plasticizer in an electrolyte composition comprising a copolymer of vinylidene fluoride (VF2) and hexafluoropropylene (HFP), the temporary plasticizer being employed to provide voids in the solid polymer after removal thereof, and the temporary plasticizer being removed in a later step and subsequently replaced by of the hygroscopic lithium salt solution. The temporary plasticizer permits the early stages of the cell formation process to be run without undue concern about moisture. Gozdz does not disclose a melt extrusion process.
Schmutz et al., U.S. Pat. No. 5,470,357, discloses melt extrusion of the compositions of Gozdz, op.cit. Schmutz teaches a process of pretreating the current collector with a solution of a polymer similar to the polymer of the solid polymer electrolyte to facilitate lamination. The lamination may be performed utilizing calender rolls. The process otherwise is similar to that of Gozdz.
Chern et al., WO 97/44847 discloses an extrusion process for forming an activated electrode suitable for use in batteries, the process comprising mixing a non-ionic polymer, an electrode-active material, a salt, and organic carbonates and feeding the mixture to the feed zone of an extruder, mixing the ingredients therein, and extruding a film suitable for laminating to other components of the battery.
Keller et al., U.S. Pat. No. 5,725,822 discloses extrusion of an activated electrode composition the process comprising feeding a mixture of a (non-ionic) polymer, an electrode-active material, a salt, and organic carbonates to the upstream end of a screw extruder, and feeding additional solvent (or possibly a mixture of polymer and solvent) at a downstream port. The amount of solvent in the first feeding stage is adjusted to provide a melt undergoing sufficient shear that good mixing will occur, and the amount of solvent being fed in the second stage being adjusted so that the total amount of solvent represents the final amount in the finished electrode material. The extruded electrode may be deposited onto a current collector and/or coated with a layer of solid polymer electrolyte. Assembly of a lithium battery cell from thus extruded components is also disclosed.
Doyle et al., WO 98/20573, disclose the use of perfluoroionomers to form the electrodes and separators of electrochemical cells. In particular, the lithium ionomers are employed to form lithium-ion cells. The electrodes and separators are formed by casting solutions and dispersions onto a substrate, followed by a drying step, which in turn is followed by a solvent contact step. Combination of these components into electrochemical cells is also disclosed.